Monitoring unknown pulsed emissions or continuous wave (CW) emissions is difficult in the presence of high level CW emissions in the monitored bandwidth. Pulsed emission monitoring in the presence of pulsed interference can be overcome using established pulse on pulse extraction techniques but CW high level interference tends to mask unknown low level pulses within the monitored bandwidth. In the past, static or adaptive filters have been used to remove CW interference, creating blind spots in the monitored bandwidth. Further, adaptive filters, for example adaptive YIG filters, have settling times which can be too slow to remove fast agile signal emissions such as very fast frequency hopped CW wideband communications emissions and are not readily adaptable to remove multiple CW spread spectrum interfering emissions.